Apparatus and method for coating multifilament glass yarn



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ATTORNE YS- United States Patent Ofice Patented Sept. 13, 1956 APPARATUS AND METHOD FOR COATING MULTIFILAMENT GLASS YARN Leo B. Clougherty, Cranston, and Robert F. Mueller, Providence, R. 1.

Application October 5, 1953, Serial No. 384,258

2 Claims. (Cl. 117.-7)

This invention relates to the coating of filamentary yarn, such for instance as glass yarn.

It has heretofore been diflicult to use yarn made of fine filaments, such for instance as glass yarn, because the fine filaments would break on the outer surface of the yarn, which had many disadvantages. Coating of such yarn has also been found difiicult, especially to obtain a coating which might permeate the yarn sufiiciently so as to become a part thereof and maintain itself in position. Further, coating was diificult because the yarn would break in attempting to pass it through a die, which was necessary to evenly distribute the coating on the yarn.

One of the objects of this invention is to overcome the above-mentioned difliculties which have been heretofore experienced.

More specifically an object of the invention is to provide a die through which the yarn may be drawn without the yarn breaking as it passes through the die.

Another object of the invention is to provide a coating which will be distributed through the fibers of the yarn by manipulation of the yarn in such a manner that the coating may be easily flowed into such position.

Another object of the invention is to provide a coating which may not only serve to protect the yarn but which may be colored so that the desired appearance may be had.

With these and other objects in view, the invention con sists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a schematic view illustrating the yarn as passing through the various operations which are performed upon it;

Figure 2 is a sectional view showing the bath, the yarn flexing means, and the die through which the yarn is drawn;

Figure 3 is a fragmental view on a larger scale showing the yarn as it passes back and forth between rods which cause it to flex and assume the flattened shape;

Figure 4 is a fragmental sectional view of a groove in the die;

Figure 5 is a sectional view on substantially line 5-5 of Figure 2 showing the die through which the yarn is drawn.

In proceeding with this invention, we draw the filamentary yarn, which in this case is glass having a multiplicity of fine filaments, through a bath of coating which is to be applied to the yarn which will be some sort of a resin and then flex the yarn back and forth between rods which spread the yarn from a cylindrical cross section to a flat form and permit the resin coating to flow in between the filaments. The yarn then passes through a die composed of rotating members and is set in heaters and then packaged on a cone or some suitable take-up means.

With reference to the drawings, a supply package is designated and comprises a filamentary yarn, such for instance as glass, which it is desired shall be coated. This yarn is passed through guides 13, 14 into a liquid bath 11 in a suitable container 12 to cause the yarn to move below the liquid level of the coating 11 and is then passed through a flexing device 15 which comprises a pair of supports 16 with rods 17, 18, and 19 extending from one support to the other, which are generally in line, so that the yarn may be moved in zigzag manner back and forth between the rods and cause the yarn to be flattened out as shown at 20 in Figure 3 so as to spread the filament sufiiciently to permit the coating 11 to flow between the filaments. Supports 16 are secured to the sides of the container 12 by screws 21 and 22.

The yarn is then passed through a die designated generally 25, which comprises a roller 26 having a plurality of grooves 27, 28, and 29 therein suificient in number for the number of yarns to be coated at one time. These grooves, such for instance as 27, are of a size about 25 per cent greater than the size of the yarn to be coated so that the coating will be evenly ironed into cylindrical form about the filaments. Co-operating with the lower roll 26 is the upper roll 30 which has a smooth cylindrical surface which engages throughout the width of the roll 26 and closses the upper edge of the grooves so as to form an eye through which each of the yarns will pass. This roll 30 is mounted on a shaft 31 having bearings 32 at its ends, which bearings are slidable toward and from the roll 26 in the upstanding supports 33. These bearings are urged toward the roll 26 by springs 34 which may be adjusted by the screws 35 bearing upon the abutments 36 which engage the upper ends of the springs 34. Such adjustments may be effected by the squared heads 37 of the screws and may be held in place by check nuts 38. The roll 26 is mounted upon a shaft 39 which has fixed bearings 40 in the frame 33, and this shaft 39 is driven from some suitable source. Gear 41 on shaft 40 and gear 42 on shaft 31 cause the interfacial surfaces of the two rolls 26 and 30 to be driven at the same surface speed, which will be selected as will hereinafter appear.

It is desirable to incline the rolls as shown in Figure 2 so that a plane passing through the axes of both rolls will be inclined to the vertical and tipped toward the fiexing device 15 and bath 11. This relieves the amount of contact which the coated yarn has with the roll 26 and enables the yarn to better be maintained in the groove which is provided for it and reduces breaking of the fi1aments of the yarn. Doctor blades 43 for roll 30 and 44 for roll 26 are used to clean the rolls and will remove and surplus coating or any broken filaments which might collect on the rolls.

After emerging from the die 25, the yarn passes through a heater 45 which subjects the coating to a temperature of from 700 to 800 F., the length of the heater being sufficient so that the yarn remains in the heater for about two thirds of a second, which gives it a quick heat set. This quick set maintains the coating round in cross section about the filaments and prevents distortion which otherwise might occur. It then emerges and passes through a second heater designated generally 46, which subjects it to a temperature of from 450 to 500 F. and is of sufficient length so that the coating is subjected to this temperature for eight seconds. These temperatures will vary in accordance with the particular coating material which is to be used. For example, the above is satisfactory for a mixture comprising by weight vinyl chloride of the dispersion polymer type parts, a plasti-cizer such as tricresyl phosphate 100 parts, a stabilizer such as lead carbonate 1 to 2 parts, and some color pigment. The purpose is to set the resin plastic by polymerization. It will be understood that many resins may be used and other plasticizers may be used, such as most any organic phosphate, another example of which is tri- Z-ethylhexyl phosphate, or the phthalate plasticizers may be used, for example dinonyl phthalate or diiso-octyl J9 phthalate. The plasticizers may vary largely in amount depending on the viscosity desired for the coating. The stabilizers may be of tin or cadmium in substitution for the basic lead carbonate. The color pigment may vary in amount with the depth of color required. A fungicide may also be added if desired.

. A feeding device designated 47 comprises a pair of rolls which are driven and about which the yarn is coiled a sufiicient number of times to obtain the tension desired for pulling the yarn from the package through the heretofore described process. The yarn is guided as at 48 in passing to the feeder 47 and is guided as at 49 in passing to the traversing bar 50 of the winding or takeup mechanism designated generally 51 and comprising a driving head 52 and a package 53 upon which the yarn is wound.

It is found in running the apparatus that it is desirable to have the surface speed of the die about 18 feet per minute when the yarn is running at 90 feet per minute. Thus, there is a slipping action of the yarn through the die. The opening in the die is about 25 per cent greater than the diameter of the thread or yarn which is to pass therethrough, thus causing the coated yarn to be about 25 per cent larger than the uncoated yarn. By moving the surface of the die, it is found that little or no fuzzing occurs, whereas a stationary die causes some fuzzing. Also by using one surface flat with the groove completely in the other of the rotating surfaces, fuzzing is found to be reduced. The quick set of the more intense heat 45 serves to keep the coated yarn cylindrical and then the remaining heat serves to provide the desired polymerization or set for maintenance of the coating in the desired condition.

The quantity of coating may be controlled to some extent by the relative speed of the die to the travel of the yarn. Thus, the faster the surface of the die, the more plastic coating will be put on, all other procedures being the same.

We claim:

1. The method of coating multifilament glass yarn of generally cylindrical form having a plurality of continuous type filaments which comprises passing the yarn through a solution of a protective coating, flattening and spreading the yarn, thereby causing flowing of the coat ing between the filaments of yarn, and then passing the coated yarn through a die encircling the yarn to restore the same into generally cylindrical form with the surfaces of the die moving in the direction of travel of the yarn as the yarn passes therethrough but at a speed less than the speed of travel of the yarn.

2. An apparatus for coating multifilament glass yarn comprising a coating bath through which the yarn passes, means for alternately flexing the yarn back and forth, a die to restore the yarn to circular shape comprising a grooved roller and a smooth roller contacting the grooved roller and closing the groove therein with the line between the axes of the rollers being inclined to the vertical toward the bath and flexing means, through which die the yarn passes, and means for heating the coated yarn.

References Cited in the file of this patent UNITED STATES PATENTS 1,316,210 Wardwell Sept. 16, 1919 1,759,326 Scholler May 20, 1930 2,133,446 Gwaltney Oct. 18, 1938 2,272,177 Madden Feb. 10, 1942 2,365,069 Grimes Dec. 12, 1944 2,398,516 Burgeni et al Apr. 16, 1946 2,426,493 Ericksson et al. Aug. 26, 1947 2,547,047 Saums et al. Apr. 3, 1951 2,558,993 Sturgis et al. July 3, 1951 FOREIGN PATENTS 548,794 Great Britain Oct. 26, 1942 

1. THE METHOD OF COATING MULTIFILAMENT GLASS YARN OF GENERALLY CYLINDRICAL FORM HAVING A PLURALITY OF CONTINUOUS TYPE FILAMENTS WHICH COMPRISES PASSING THE YARN THROUGH A SOLUTION OF A PROTECTIVE COATING, FLATTENING AND SPREADING THE YARN, THEREBY CAUSING FLOWING OF THE COATING BETWEEN THE FILAMENTS OF YARN, AND THEN PASSING THE COATED YARN THROUGH A DIE ENCIRCLING THE YARN TO RESTORE THE SAME INTO GENERALLY CYLINDRICAL FORM WITH THE SURFACES OF THE DIE MOVING IN THE DIRECTION OF TRAVEL OF THE YARN AS THE YARN PASSES THERETHROUGH BUT AT A SPEED LESS THAN THE SPEED OF TRAVEL OF THE YARN. 